Field of the Invention
The present invention relates to a channel switch control technique in wireless communication.
Description of the Related Art
Wireless LAN communication systems, which are represented by IEEE802.11 standard series, are widely used. With a wireless LAN, a base station called an access point (hereinafter, an AP) and a station (hereinafter, a STA) that exists within an area within which a radio wave of the AP can reach and that is in a wirelessly connected state establish a connection, establish a network, and wirelessly communicate with each other. In recent years, methods have emerged for performing communication not only with a simple wireless network configuration using conventional APs and STAs, but also in various modes of wireless LAN network. For example, Tunneled Direct Link Setup (TDLS) is a technique for communication between STAs that are connected to an AP, using a direct connection (direct link). IEEE Std 802.11-2012 describes a technique of forming a direct connection between wireless STAs by transmitting and receiving control data for setting TDLS via an AP between wireless LAN terminals. Since each wireless LAN terminal directly communicates with a partner terminal by forming a direct connection, communication can be performed that is not affected by restriction due to the capability of the AP.
With TDLS, a channel for direct communication between STAs is not fixed to a channel (hereinafter referred to as a “base channel”) of a wireless network configured by the AP in a wireless network and can be switched to another channel (hereinafter referred to as an “off-channel”). As a result, for example, even when the AP operates with 2.4-GHz band, a STA can directly communicate with a partner STA by using a 5-GHz band channel.
Wi-Fi Display is video streaming communication using a direct connection by means of TDLS. Wi-Fi Display is a wireless direct streaming technique that is standardized by Wi-Fi Alliance. In Wi-Fi Display, a device that transmits video streaming is called a Source, and a device that receives video streaming is called a Sink. In Wi-Fi Display, either Wi-Fi Direct or TDLS is used for wireless connection. Communication devices that use Wi-Fi Display can transmit and receive video streaming therebetween without via an AP, as a result of establishing a direct connection using TDLS. As a result of switching of the channel by means of TDLS, the communication devices become able to transmit and receive video streaming with 5-GHz band, with which interference is relatively small, for example.
In the current situation, a consideration is not given to the influence of communication devices establishing a direct connection using TDLS and switching their channel on other direct connections that are established at this time point. That is to say, for example, problems in the case where a communication device, which has established a direct connection with a plurality of other communication devices, switches its channel for direct communication with one of the plurality of other communication devices have not been examined.
The present invention has been made in view of the aforementioned problem, and provides a technique for controlling a direct connection of a communication device with other communication devices, based on a state of other connection.